Wood chipping knife



WOOD CHIPPING KNIFE Filed Aug. 10, 1966 Sheet I of 2 FIG-I INVENTORS I ADRIAN ARTIANO 8 VERNE L. LINDBERG M /M w ATTORNEYS Jan. 14, 1969 A. ARTIANO ET AL WOOD CHIPPING KNIFE Filed Aug. 10, 1966 Sheet 3 of 2 United States Patent 7 Claims This invention relates to wood chipping apparatus, and more particularly, to an improved knife adapted to be used on chipping apparatus for converting logs and other wood pieces into small chips having long fibers.

Knives constructed in accordance with the present invention are ideally suited for use in the chipping apparatus disclosed in copending application Ser. No. 536,765, filed Mar. 23, 1966 and assigned to the same assignee as the present invention. It is to be understood, however, that these knives may also he used on other forms of wood chipping apparatus.

Basically, the chipping apparatus discloesd in the above application includes a hollow rotor having a generally frusto-conical shaped wall. A series of knives are arranged in a spiral-like manner on the rotor wall and project inwardly from corresponding openings formed within the wall. As a log or other wood piece is fed into the rotor generally parallel to its axis of rotation, the knives engage the end portion of the log and progressively cut the log into chips which are discharged centrifugally outwardly through the knife openings.

It has been found desirable to construct the knives for the above wood chipper from flat metal stock either by a stamping or a drop forging operation to minimize the cost of a set of knives. Thus when the knives become dull, it is usually more economical to dispose of them and replace them with a new set rather than have the dull knives resharpened. While it is desirable to minimize the cost of the knives, however, it is also desirable to construct the knives in such a manner as to obtain maximum service life before the knives require replacement.

Accordingly, it is a primary object of the present invention to provide an improved knife of economical construction and adapted to be used on wood chipping apparatus for producing chips having long fibers.

More specific objects of the invention are to provide an improved knife as outlined above and which may be readily formed from fiat metal stock of uniform thickness by a stamping or a dropped forging operation; to provide a knife as outlined above and including surface means adapted to provide a self-feeding action of the wood into engagement wtih the knife; to provide an improved knife including at least two spaced apart cutting edges and means for selectively mounting the knife to present each cutting edge for engagement with the wood; and to provide an elongated knife including a primary cutting edge formed on each end for splitting the wood at a predetermined depth corresponding to the desired thickness of the chips and further including a lead cutting edge extending angularly from each primary cutting edge for cutting the wood cross-grain to form chips of predetermined uniform length.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings:

FIG. 1 is a perspective view of chipping apparatus employing knives constructed in accordance with the invention;

FIG. 2 is a view of the apparatus of FIG. 1 with the housing removed and with the rotor in section to show generally the arrangement and position of the knives;

FIG. 3 is a fragmentary section of the rotor taken gen- 3,421,561 Patented Jan. 14, 1969 erally along the lines 3--3 of FIG. 2 and FIG. 5 and showing a knife in elevation;

FIG. 4 is a fragmentary perspective view of the rotor and showing the inwardly projecting end portion of a knife;

FIG. 5 is a view taken generally along the line 5-5 of FIG. 3 and showing a knife mounted on the rotor;

FIG. 6 is an end view of the knife of FIGS. 3-5;

FIG. 7 is a fragmentary section of a knife as taken generally along the line 7-7 of FIG. 5;

FIG. 8 is a fragmentary section of the knife taken generally along the line 8-8 of FIG. 6; and

FIG. 9 is an elevational view of the knife showing the opposite side from that shown in FIG. 5.

Referring to the drawings, which illustrate a preferred embodiment of the invention, an assembled wood chipper similar to that shown in the above application, is shown in FIG. 1 and generally includes a base 12 in which is formed a semicylindrical cavity 14 (FIG. 2). A pair of bearings 16 and spacing blocks 17 are mounted on the 'base 12 for rotatably supporting a rotor 20 by its shaft 21 which has a reduced end portion 22 extending through the rear bearing 16. A pulley 23 is mounted on the reduced end portion 22 of the main shaft 21 and is connected by V-belts 24 to a motor 25 supported by a bracket 27 mounted on the base 12.

As shown in FIG. 2, the rotor 20 includes a circular rear plate 28 which is rigidly secured to the shaft 21 and reinforced by ribs 29. An annular frusto-conical wall member 30 is rigidly mounted on the plate 28 by a series of screws 32 and defines generally an inner frusto-conical surface 34 which is interrupted by one or more spiral or helically formed lands 36. Preferably, each land 36 extends parallel to the axis of the shaft 21 and forms one or more revolutions on the surface 34.

Formed within the wall member 30 and uniformly spaced around the the spiral land 36 (FIG. 2) are a series of generally V-shaped openings 38 defined by angularly disposed surfaces 39 and 40 (FIG. 3). A threaded hole 41 and a pair of holes 42 evenly spaced from the hole 41 are formed within the wall member 30 and extend from the surface 40 of each opening 38. Dowels 43 are mounted within the holes 42. and project from the surface 40. Also formed as a rigid part of the rotor 20 are a series of vanes 44 (FIG. 2) which project outwardly from the wall member 30 to act as fan blades.

A tubular spout member 45 (FIGS. 1 and 2) having a support frame 46 is mounted on the base 12 by a series of screws extending through the frame and into a spacing block 48. As shown in FIG. 2, the spout member 45 has a horizontal axis which extends parallel to the axis of the shaft 21. The inner end portion 49 (FIG. 2) of the spout member 45 is beveled generally parallel Within the inner surface 34 of the rotor 20.

Located within each of the openings 38 formed within the rotor 20 is a knife 50 which preferably is formed by a stamping or forging operation from flat metal stock of uniform thickness. In accordance with the present invention, each knife 50 has generally a parallelogram configuration (FIGS. 5 and 9) and includes a base portion 52 having flat parallel edge surfaces 53 (FIG. 9). A beveled end surface 54 (FIG. 7) is formed across each end of the base portion 52 and cooperates with a side surface 55 to form a straight primary cutting edge 56. As shown in FIGS. 5 and 9, each primary cutting edge 56 forms an angle A of approximately with the adjacent edge surface 53 of the base portion 52.

Referring to FIG. 5, each half of the base portion 52 is provided with a longitudinal edge portion 58 which extends at an angle B (FIG. 6) of approximately 126 from the base portion 52. A beveled end surface 60 (FIG. 8)

is formed on the end of each edge portion 58 and cooperates with a side surface 61 of the edge portion to form a straight lead cutting edge 62 which extends angularly from the primary cutting edge 56 as shown in FIG. 4.

Referring to FIGS. 7 and 8, preferably the beveled end surface 54 on each end of the base portion 52 and the beveled end surface 60 on each edge portion 58 (FIG. 8) are formed at an angle D of approximately 25 with the side surfaces 55 and 61 respectively. As shown in FIG. 5, the side surface 61 of each edge portion 58 joins a side surface 55 of the base portion 52 to describe a line 64 (FIG. which extends at an acute angle F of approximately 80 with the corresponding primary cutting edge 56.

Each knife 50 is provided with a central hole 65 (FIG. 9) within the base portion 52 for mounting the knife within an opening 38 within the rotor wall 30 by a screw 66. In addition, the base portion 52 of each knife is provided with a pair of holes 68 equally spaced from the central hole 65 for receiving the dowels 43 extending from the holes 42. It is to be understood, however, that a plurality of knives 50 may be mounted on a single support bar which is adapted to be mounted within a corresponding slot formed within the rotor wall 30 as disclosed in the above mentioned application. The use of a series of support bars provides for quick replacement of the knives after the cutting edges on both ends of the knives become dull.

As shown in FIGS. 2 and 5, the knives 50 are positioned on an inclined angle relative to the axis of the shaft 21 so that the primary cutting edge 56 of each knife extends parallel to the axis of the shaft and to the land 36 from which it projects. Thus when a log L is fed into the tubular spout 45 from supporting rollers 70 or a feed conveyor, the log is positioned so that its axis extends parallel to the primary cutting edge 56 of each knife 50. Referring to FIGS. 2 and 3, the rotor is rotated clockwise causing the knives 50 to cut successively through the end portion of the log and produce chips which are thrown outwardly through the openings 38. The chips are propelled by the fan blades 43 for discharge from an outlet 72 formed within a removable hood member 74.

Since the primary cutting edge 56 of each knife remains parallel at all times to the axis of the log, the primary cutting edge splits through the end portion of the log while the lead cutting edge 62 shears diagonally across grain through the log. This results in producing chips which have a parallelogram cross-sectional configuration as shown in the above application and with the grain and fibers extending the length of the chips. The splitting of the chips from the wood in this manner also results in producing a tapered step-like surface across the end of the log, as shown in the above application, and in minimizing the power required from the rotor 26 for driving the rotor 20.

Due to the angular position of the knives 50 within the corresponding openings 38, the side surface 61 extending from the lead cutting edge 62 passes through the end portion of the log at an inclined angle relative to the log axis. This inclined position of the surface 61 tends to pull the log L inwardly through the spout 45 and into engagement with the primary cutting edge 56.

One important feature provided by a knife 50 constructed in accordance with the invention is its long service life. That is, when the cutting edges 56 and 62 formed on one end of the knife becomes dull, the knife is simply inverted so that the cutting edges on the opposite end of the knife project through the corresponding opening 38 as shown in FIG. 4. This can be conveniently and quickly accomplished simply by removing the single retaining screw 66 and inverting the knife on the dowels 43, or if knife support bars are used, merely by loosening the retaining screws 66 and inverting the knives on the bars.

Another important feature provided by a knife constructed in accordance with the invention is that each knife can be easily formed at a low cost from commercially available fiat metal stock. That is, by constructing each knife with a generally parallelogram configuration and by forming the edge portions 58 angularly from the flat base portion 52, each end portion of the knife not only provides cutting edges 56 and 62 but also provides a sloping side surface 61 for producing a self-feeding action.

While the form of knife herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of knife, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. An improved knife for use on chipping apparatus to convert logs and other wood pieces into small chips having long fibers, comprising a base portion having a flat side surface, an edge portion having a side surface extending angularly from said side surface of said base ortion, a beveled end surface on said base portion c0- operating with the corresponding said side surface to form a primary cutting edge, a beveled end surface on said edge portion cooperating with the corresponding said side surface to form a lead cutting edge extending angularly from said primary cutting edge, said side surface of said edge portion and said side surface of said base portion joining to describe generally a line forming an acute angle with said primary cutting edge, and means for mounting said knife on the chipping apparatus so that said primary cutting edge cuts through the 'wood generally parallel to the grain while said lead cutting edge cuts across grain and said side surface on said edge portion urges the wood into engagement with said primary cutting edge to provide a self-feeding action.

2. A knife as defined in claim 1 wherein said base portion and said edge portion are generally uniform in thickness, and said edge portion forms an obtuse angle with said base portion causing said lead cutting edge to form an obtuse angle with said primary outing edge so that said lead cutting edge cuts diagonally across the grain of the wood while said pirmary cutting edge cuts with the grain to minimize power for driving the chipping apparatus.

3. A knife as defined in claim 1 comprising a plurality of edge portions extending angularly from said base portion, a corresponding plurality of said beveled end surfaces on said base and edge portions for cooperating with corresponding said side surfaces to form a plurality of said primary cutting edges and corresponding said lead cutting edges, and said mounting means including means for selectively positioning said knife to locate each said primary cutting edge and corresponding said lead cutting edge in position to engage the wood for providing a knife having a substantially long service life.

4. A knife as defined in claim 3 wherein said base portion and said edge portions are generally uniform in thickness and formed from fiat metal stock, and each said lead cutting edge forms an obtuse angle with the corresponding said primary cutting edge.

5. A knife as defined in claim 4 wherein said base portion is elongated and comprising primary cutting edges formed on opposite ends of said base portion, and each said edge portion projecting from said base portion in corresponding relationship to provide for simply inverting the knife when said primary and lead cutting edges on one end become dull.

6. A knife as defined in claim 5 wherein said angularly extending edge portions extend in parallel relationship, and said base portion includes parallel longitudinal edge surfaces each forming an obtuse angle with the adjacent said primary cutting edge to form a knife having generally a parallelogram configuration.

7. A knife as defined in claim 5 wherein said mounting means comprises means defining a central opening within aid base portion for receiving a retaining screw, and

5 6 means defining a pair of holes Within said base portion 3,190,326 6/1965 Standal 144-162 spaced equidistant from said central opening for receiv- 3,219,076 11/1965 Logan et 'al. l44-241 X ing corresponding locating dowels so that each said knife 3,294,132 12/ 1966 Little 144-218 can be readily inverted and precisely positioned simpl 3,304,970 2/1967 Altosaar 144-162 by removing the retaining screw. 5

ANDREW R. JUHASZ, Przmary Examiner.

References Cited FRANK T. YOST, Assistant Examiner. UNITED STATES PATENTS U.S. C1.X.R.

3,011,535 12/1961 Andrus et a1 144-241); 10 -1 

1. AN IMPROVED KNIFE FOR USE ON CHIPPING APPARATUS TO CONVERT LOGS AND OTHER WOOD PIECES INTO SMALL CHIPS HAVING LONG FIBERS, COMPRISING A BASE PORTION HAVING A FLAT SIDE SURFACE, AN EDGE PORTION HAVING A SIDE SURFACE EXTENDING ANGULARLY FROM SAID SIDE SURFACE OF SAID BASE PORTION, A BEVELED END SURFACE ON SAID PORTION COOPERATING WITH THE CORRESPONDING SAID SIDE SURFACE TO FORM A PRIMARY CUTTING EDGE, A BEVELED END SURFACE ON SAID EDGE PORTION COOPERATING WITH THE CORRESPONDING SAID SIDE SURFACE TO FORM A LEAD CUTTING EDGE EXTENDING ANGULARLY FROM SAID PRIMARY CUTTING EDGE, SAID SIDE SURFACE OF SAID EDGE PORTION AND SAID SIDE SURFACE OF SAID BASE PORTION JOINING TO DESCRIBE GENERALLY A LINE FORMING AN ACUTE ANGLE WITH SAID PRIMARY CUTTING EDGE, AND MEANS FOR MOUNTING SAID KNIFE ON THE CHIPPING APPARATUS SO THAT SAID PRIMARY CUTTING EDGE CUTS THROUGH THE WOOD GENERALLY PARALLEL TO THE GRAIN WHILE SAID LEAD CUTTING EDGE CUTS ACROSS GAIN AND SAID SIDE SURFACE ON SAID EDGE PORTION URGES THE WOOD INTO ENGAGEMENT WITH SAID PRIMARY CUTTING EDGE TO PROVIDE A SELF-FEEDING ACTION. 